Fastening for removable dental bridges and bridge-plates.



C. W. LOKEY.

FASTENING FOR REMOVABLE DENIAL BRIDGES AND BRIDGE PLATES.

- APPLICATION FILED JULY 16. 1911.

1,299,364, I Patented Apr. 1 1919.-

s "UITE CHARLES W. LOKEY, 0F BIRMINGHAM, ALABAMA.

FASTENING FOR REMOVABLE DENTAL BRIDGES AND BRIDGE-PLATES.

Specification of Letters Patent.

seamed Apr. 1, 1919.

Application filed July 16, 1917. Serial No. 180,702.

To all whom it may concern." V

\ Be it known that I, CHARLES W. LOKEY, a citizen of the United Statesof America, residing at Birmingham, in the county of Jefferson and Stateof Alabama, have invented certain new and useful Improvements inFastenings for Removable Dental Bridges and Bridge-Plates, of which thefollowing is a specification.

My invention relates to fastenings for removable dental bridges andbridge plates which will permit the abutment tooth to which the bridgeor plate is fastened, to have a free normal movement during masticationwithout straining or breaking the joint between the fastening elementsor their respective connections to the abutment and bridge or bridgeplate.

My present invention is more especially intended as an improvement onthe type of dental fastening described in Letters Patent of the UnitedStates No. 1,193,034, issued to me on the 16th day of August, 1916, andwhich comprises a keeper, formed of hard metal shaped to provide sidegrooves and preferably a top groove alining with the side grooves, andan anchor attachment for the removable bridge or bridge plate, which isformed of bent wire (preferably drawn wire of hard metal such as iridioplatinum) that is shaped to fit snugly into the grooves of the keeperand to interlock firmly therewith so that the fastening resists withmuch strength any relative movement between the keeper and anchor exceptin the direction in which the bridge or bridge plate is moved to detachit from. the abutment.

According to my present invention the web of the keeper and the sides ofthe anchor which engage it are so shaped as to permit a limited rockingplay to take care of the normal -movement between keeper and an chor ina transverse plane through the joint. Provision for this play can bemade by mak ing the web of the keeper in transverse cross-sectionelliptic or wider at its center than at its ends, and leaving the sidesof the anchor that engage the keeper straight, or the same play may beobtained where the sides of the web are straight and provision for therocking play is made in the shape of thei) parts of the anchor whichengage the We 1' v a My present invention further contemplatescontracting the anchor by slightly drawing or bending in either or bothsides thereof near the neck so that it will snap over the thickercentral portionof'an elliptic keeper web and'securely prevent accidentaldisconnection of the fastening elements without, however, interferingwith the limited play that makes provision for normal movements of thebridge or the abutment tooth.

A further objectof my invention is to improve the construction of thekeeper proper by tapering its end next to the gum so that it is inclinedaway from the gum. This arrangement will prevent food collecting betweenthe keeper and gum and make it easier to keep the parts clean.

'My invention further comprises the novel details of construction andarrangements of parts which in their preferred embodi ments only areillustrated in the accompanying drawings which form a part of thisspecification, and in which Figure 1 is a plan view illustrating thelower jaw with a bridge plate attached by my improved fastening andpartly broken away.

Fig. 2 is a perspective view of the anchor.

and keeper detached, the keeper being shown attached to a tooth orabutment.

Fig. 3 is an enlarged sectional view through the abutment showing theassembled anchor and keeper in side elevation.

Fig. 4 is a view showing the anchor in front elevation mounted in abridge orbridge plate.

Fig. 5- is an enlarged vertical sectional view taken on the line 5-5 ofFig. 3, with the anchor shown in elevation.

Fig. 6 is a view similar to Fig. 5 of a modification of my invention inwhich the sides of the web are straight and the anchor loop enlarged toprovide for the rocking play desired.

Similar reference numerals refer to similar parts throughout thedrawings.

In the embodiment of my invention illustrated, a detachable bridge plateis adapted to be attached to abutments 1 which may be of any suitableconstruction and attached to any desired, natural teeth as may be bestsuited for each individual case. To each abutment I- solder or otherwiseattach an elliptic shape.

a keeper which is formed of a block of hard metal having a flat frontface 2 which is connected by an integral shankor' web 3 with a back face4 which is preferably thinner than the front face and adapted to be soldered to the abutment. The web, which is formed by the side grooves inthe keeper, is preferably cut away below the top or outer endcdge ofthekeeper so as to form a top groove or seat for the anchor. The web, asshown in Figs. 1 to 5, is made thicker at or slightly below its center(see Fig. 5) and it istapered or made thinner toward its top and bottomends so as to give it in vertical cross section what may be termedgenerally The inner end of the keeper adjacent to the gum is beveledaway from the abutment and gum as indicated by the outwardly slopingface 5.

The bridge plate 6 has firmly embedded therein an anchor, preferablyformed of drawn wire or hard metal. It comprises ends 7 which arerigidly embedded in the rubber saddle of the bridge plate or they may berigidly attached in any other suitable manner to a metal saddle or tothe bridge or bridge plate. The wire is bent upwardly to form a loopportion 8, the bases of the sides of which .are bent outwardly andhorizontally at 9 to join the ends 7 which lie in a plane at rightangles to that of the loop. The sides of the loop, as shown in Fig. 2,are straight and correspond to the construction shown in Fig. 8 of myLetters Patent hereinbefore referred to, as such form can be used withmy improved keeper, but I prefer to contract the neck of the anchor loopby drawing in its sides as at 10 (Figs. l and Itis preferable that bothsides of the loop be thus drawn in but not essential as a snap lockcould be obtained by contracting the neck of the loop in any manner.

From a consideration of Fig. 5 it will be apparent that when the keeperand anchor loop are interlocked, the keeper is free' to rock in theanchor within predetermined limits in either direction, as indicated bythe. arrow, and thus allow for the normal play or movement of theabutment tooth during masticatlon, and it is conversely true that thebridge plate itself can have a like keeper and the anchor would prove anunsat1sfactory fastening fora bridge or bridge plate. By contracting theneck of the loop it will snap into place about the keeper web and canonly be disengaged by a strong pull upwardly or downwardly according towhetherthe bridge is carried by the upper or lower jaw. In Fig. 6 I showthe keeper web 11 formed with parallel sides and the top 12 of theanchor loop is struck onan arc from the center of the web and made aswide as :is necessary to provide for the rocking play desired. The sidesof the loop are bent in at 1 3 to engagethesides ofvthe web and are thenbent out away from'the sides thus forming side bearings which willpermit the keeper and anchor to rock relatively.

The essential feature of my invention :is that the keeper and anchor bedesigned :to permit only sufiicient relative rocking movements to avoidundue strains on the fastenings or abutments that would .otherwiseiresalt from normal toot-h movements during mastication.

Having thus described'my invention, what I claim as new and desire tosecureby Letters Patent, is:-

1. In a dental fastening, in combination, a keeper having a head and avertically elongated shank which tapers in width toward one end, and ananchor having sides which straddle the shank behind the head and clampbetween them the widest portion thereof, clearance being left between*the sides and narrow end of the shank to permit only a limited rockingmovement of the shank in the anchor and of the anchor on the shank.

2. In a dental fastening, in combination, a keeper having side grooves,and an anchor adapted to straddle the keeper and :engage it topreventboth downward and lateral play .in the joint, there being aclearance provided above and below the points of contact between thesidesof the keeper and the anchor to permit only a predeterminedrelative rocking movement in the joint between the anchor and keeper, asand for-the purposes described.

3. In a dental fastening, in combination, a keeper having opposite sidegrooves .which leave between them a substantially elliptical shaped webdisposed with its long axis vertical, and an anchor formed of bent wirehaving closely spaced side members aclapted tobe received in saidgrooves and in normal position to yieldingly engage the said web onlyopposite its'short axis.

4-. In a dental fastening, a keeper formed of an elongated body of hardmetal having in its opposite side faces longitudinal grooves which shapethe body into front and back wallsconnected by a longitudinal andrelatively narrow central web which tapers toward both end edges of thekeeper.

5. In a dental fastening, an anchor ment With a keeper, one of the sidesof said formed of hard metal Wire having a portlon eye being bent tocontract its end adjacent thereof adapted for attachment to the bridgeto the bridge or bridge plate. 10 or bridge plate, and having portionsthereof In testimony whereof I affix my signature. 5 spaced from saidattachment portion and CHARLES W. LOKEY.

bent at an angle thereto into closely spaced Witness: parallelism toform a clasp eye for engage- NoMIE WELSH.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

